What is the ruling on sighing (exhaling with a sound), and is it permissible, forbidden, or disliked, and why?

Murmuring (uff) against parents is forbidden because of the prohibition mentioned in the verse: "So do not say to them, 'uff.'" Murmuring against Allah the Almighty is even more strictly forbidden, as it indicates vexation and lack of patience. The Prophet, peace be upon him, said: "The greatest reward comes with the greatest trial. When Allah loves a people, He tests them. Whoever is pleased, for him is pleasure; and whoever is displeased, for him is displeasure." As for other than what has been mentioned, it is disliked because it contradicts noble manners.